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-df [-h] [path …] :
Shows the capacity, free and used space of the filesystem. If the filesystem has
multiple partitions, and no path to a particular partition is specified, then
the status of the root partitions will be shown.

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-ls [-d] [-h] [-R] [path …] :
List the contents that match the specified file pattern. If path is not
specified, the contents of /user/currentUser will be listed. Directory entries
are of the form:
permissions – userId groupId sizeOfDirectory(in bytes)
modificationDate(yyyy-MM-dd HH:mm) directoryName
and file entries are of the form:
permissions numberOfReplicas userId groupId sizeOfFile(in bytes)
modificationDate(yyyy-MM-dd HH:mm) fileName
-d Directories are listed as plain files.
-h Formats the sizes of files in a human-readable fashion rather than a number
of bytes.
-R Recursively list the contents of directories.

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hdfs dfs-ls/tmp

hdfs dfs-ls-d/tmp

hdfs dfs-ls-h/tmp

Found4items

-rw-r--r--3hdfs supergroup142014-12-1810:00/tmp/hadoop.txt

-rw-r--r--3hdfs supergroup122014-12-1810:00/tmp/hdfs.txt

-rw-r--r--3hdfs supergroup1G2014-12-1810:19/tmp/test.zero

drwxr-xr-x-hdfs supergroup02014-12-1810:07/tmp/txt

hdfs dfs-ls-R-h/tmp

-rw-r--r--3hdfs supergroup142014-12-1810:00/tmp/hadoop.txt

-rw-r--r--3hdfs supergroup122014-12-1810:00/tmp/hdfs.txt

-rw-r--r--3hdfs supergroup1G2014-12-1810:19/tmp/test.zero

drwxr-xr-x-hdfs supergroup02014-12-1810:07/tmp/txt

drwxr-xr-x-hdfs supergroup02014-12-1810:07/tmp/txt/hello

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-checksum src … :
Dump checksum information for files that match the file pattern src to stdout.
Note that this requires a round-trip to a datanode storing each block of the
file, and thus is not efficient to run on a large number of files. The checksum
of a file depends on its content, block size and the checksum algorithm and
parameters used for creating the file.

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-appendToFile localsrc … dst :
Appends the contents of all the given local files to the given dst file. The dst
file will be created if it does not exist. If localSrc is -, then the input is
read from stdin.

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hdfs dfs-appendToFile*.txthello.txt

hdfs dfs-cathello.txt

Hello,Hadoop

Hello,HDFS

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-tail [-f] file :
Show the last 1KB of the file.

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hdfs dfs-tail-fhello.txt

#waiting for output. then Ctrl + C

#another terminal

hdfs dfs-appendToFile-hello.txt

#then type something

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-cp [-f] [-p | -p[topax]] src …

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hdfs dfs-stat/tmp/hadoop.txt

2014-12-1802:00:08

hdfs dfs-cp-p-f/tmp/hello.txt/tmp/hello.txt.bak

hdfs dfs-stat/tmp/hadoop.txt.bak

hdfs dfs-rm/tmp/not_exists

rm:`/tmp/not_exists':No such fileordirectory

echo$?

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hdfs dfs-rm-f/tmp/123321123123123

echo$?

0

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-count [-q] path … :
Count the number of directories, files and bytes under the paths
that match the specified file pattern. The output columns are:
DIR_COUNT FILE_COUNT CONTENT_SIZE FILE_NAME or
QUOTA REMAINING_QUOTA SPACE_QUOTA REMAINING_SPACE_QUOTA
DIR_COUNT FILE_COUNT CONTENT_SIZE FILE_NAME
-du [-s] [-h] path … :
Show the amount of space, in bytes, used by the files that match the specified
file pattern. The following flags are optional:
-s Rather than showing the size of each individual file that matches the
pattern, shows the total (summary) size.
-h Formats the sizes of files in a human-readable fashion rather than a number
of bytes.
Note that, even without the -s option, this only shows size summaries one level
deep into a directory.
The output is in the form
size name(full path)

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hdfs dfs-count/tmp

331073741850/tmp

hdfs dfs-du/tmp

14/tmp/hadoop.txt

12/tmp/hdfs.txt

1073741824/tmp/test.zero

0/tmp/txt

hdfs dfs-du-s/tmp

1073741850/tmp

hdfs dfs-du-s-h/tmp

1.0G/tmp

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-chgrp [-R] GROUP PATH… :
This is equivalent to -chown … :GROUP …
-chmod [-R] MODE[,MODE]… | OCTALMODE PATH… :
Changes permissions of a file. This works similar to the shell’s chmod command
with a few exceptions.
-R modifies the files recursively. This is the only option currently
supported.
MODE Mode is the same as mode used for the shell’s command. The only
letters recognized are ‘rwxXt’, e.g. +t,a+r,g-w,+rwx,o=r.
OCTALMODE Mode specifed in 3 or 4 digits. If 4 digits, the first may be 1 or
0 to turn the sticky bit on or off, respectively. Unlike the
shell command, it is not possible to specify only part of the
mode, e.g. 754 is same as u=rwx,g=rx,o=r.
If none of ‘augo’ is specified, ‘a’ is assumed and unlike the shell command, no
umask is applied.
-chown [-R] [OWNER][:[GROUP]] PATH… :
Changes owner and group of a file. This is similar to the shell’s chown command
with a few exceptions.
-R modifies the files recursively. This is the only option currently
supported.
If only the owner or group is specified, then only the owner or group is
modified. The owner and group names may only consist of digits, alphabet, and
any of [-_./@a-zA-Z0-9]. The names are case sensitive.
WARNING: Avoid using ‘.’ to separate user name and group though Linux allows it.
If user names have dots in them and you are using local file system, you might
see surprising results since the shell command ‘chown’ is used for local files.
-touchz path … :
Creates a file of zero length at path with current time as the timestamp of
that path. An error is returned if the file exists with non-zero length

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-setrep [-R] [-w] rep path … :
Set the replication level of a file. If path is a directory then the command
recursively changes the replication factor of all files under the directory tree
rooted at path.
-w It requests that the command waits for the replication to complete. This
can potentially take a very long time.